Increasingly, companies are seeing rapid access to key information as the way to maintaining a competitive advantage. To provide immediate access to this information, mobile and other intermittently-connected computing devices are quietly and swiftly becoming an essential part of corporate networks—especially with the proliferation of inexpensive laptops and hand-held computing devices. However, integrating these nomadic devices into existing network infrastructures has created a challenge for the information manager.
Many problems in mobile networking parallel the difficulties in early local area networks (LANs) before the adoption of Ethernet. There are a variety of mobile protocols and interfaces, and because standards are just developing, there is little interoperability between systems. In addition, performance over these network technologies has typically been slow and bandwidth limited. Implementation costs to date have been high due the specialized nature of deployed systems.
Along with these issues, mobile technologies present a category of problems unto their own. Interconnects back into the main network may travel over and through a public network infrastructure, thus allowing sensitive information to possibly be tapped into. Furthermore, if any of the intermediary interconnects are via a wireless interface, the information is actually broadcast, and anyone with a similar interface can eavesdrop without much difficulty.
But, perhaps even more significantly, mobile networking has generally in the past been limited to mostly message-oriented or stateless applications—and thus has not been readily adaptable for existing or new corporate applications that use client/server, host-terminal, web-based or shared file systems models. This is because such commonly used applications need stateful sessions that employ a continuous stream of data—not just a stateless packet exchange—to work effectively and reliably.
To this end, many or most popular off-the-shelf networking applications require TCP/IP sessions, or private virtual circuits. These sessions cannot continue to function if they encounter network interruptions, nor can they tolerate roaming between networks (i.e., a change of network addresses) while established. Yet, mobile networking is, by its nature, dynamic and unreliable. Consider these common scenarios encountered in mobile networks:
Disconnected or Out of Range User
When a mobile device disconnects from a given network or loses contact (e.g., through an outage or “hole” in the coverage of a wireless interconnect), the session-oriented application running on the mobile device loses its stateful connection with its peer and ceases to operate. When the device is reattached or moves back into contact, the user must re-connect, log in again for security purposes, find the place in the application where work was left off, and possibly re-enter lost data. This reconnection process is time consuming, costly, and can be very frustrating.
Moving to a Different Network or Across a Router Boundary (Network Address Change)
Mobile networks are generally segmented for manageability purposes. But the intent of mobile devices is to allow them to roam. Roaming from one network interconnect to another can mean a change of network address. If this happens while the system is operational, the routing information must be changed for communications to continue between the associated peers. Furthermore, acquiring a new network address may require all of the previously established stateful application sessions to be terminated—again presenting the reconnection problems noted above.
Security
As mentioned before, companies need to protect critical corporate data. Off-the-shelf enterprise applications are often written with the assumption that access to the physical network is controlled (i.e., carried within cables installed inside a secure facility), and security is maintained through an additional layer of authentication and possible encryption. These assumptions have not been true in the nomadic computing world—where data is at risk for interception as it travels over public airways or public wire-line infrastructures.
Example IPv4/IPV6 Gatewaving Services
Further to the exemplary illustrative non-limiting functionality outlined above, another capability is emerging throughout the industry. Due to the potential exhaustion of Internet Protocol Version 4 address space, the industry deemed it necessary to develop a new standard that will extend and enhance the networking layer functionality for IP based networks (as initially described in IETF RFC 1863, October 1995, incorporated herein by reference). However, to increase the available address space, a new format was devised. This new format is larger, thus rendering some existing networking infrastructure and end system technologies incompatible with the new IP protocol.
The IETF has recognized this deficiency, however the solution that has been standardizes is to encapsulate IPv4 packets within IPv6 packets or visa versa, thus enabling either protocol to traverse existing network infrastructure known colloquially as “6over4” and “4over6”. Furthermore, there are discrepancies between the IPv4 and IPv6 IP protocol specifications with regards to how each deals with mobility.
Having to deploy multiple “protocol stacks” to ensure interoperability depending on what environments the device might be coupled to at any one point in time, may cause an undue burden for a number of reasons:                some end systems may not be able to be (easily) modifiable, thus unable to achieve additional functionality        The end systems may not have the available capacity necessary for the additional overhead or processing        Inherent incompatibilities in the way each protocol version deals with the aspects of mobility        Even if the end systems could be modified, executing dual protocol stacks requires additional administration and configuration overhead        
Thus there is an emerging need to enable proxy based approaches as described above that will allow Mobile End Systems (whether fixed or not) to use underlying network infrastructure regardless of what version of Internet Protocol is being used.